Thin-film-transistor is a type of field effect transistor. Due to high electron mobility, small sub-threshold swing, and low off-state current, thin-film-transistors are often essential components in flat panel display (e.g., liquid crystal display), and play an important role in display performance.
A thin-film-transistor may include an active layer, a source electrode, a gate electrode, and a drain electrode. The active layer may be divided into a source region, a drain region, and a channel region. In a thin-film-transistor, a contact resistance between the source and drain electrodes and the active layer, and a channel region resistance may be the key factors in determining the quality of the thin-film-transistor component. In operation of the thin-film-transistor, a small contact resistance between the source and drain electrodes and the active layer and a high carrier concentration are often desired. The channel region needs to be in a semiconducting state. A high resistance and a low carrier concentration in the channel region are often desired.
In existing technology, the contact resistance between the source and drain electrodes and the active layer and the channel region resistance are often improved by plasma bombardment of the active layer. For example, the channel region may be treated by N2O and O2 plasma to increase the channel region resistance. The source region and the drain region may be treated by He and Ar plasma to reduce the contact resistance between the source and drain electrodes and the active layer. However, the plasma bombardment of the surface of the active layer may change the surface structure of the active layer, and cause a reduction in carrier mobility. Further, carriers may diffuse from high concentration region into low concentration region. The carrier diffusion may increase the carrier concentration in the channel region, and change on-off characteristics of the component. To certain extent, the semiconductor is turned into a conductor, and the thin-film-transistor is turned into a conducting state, thereby causing instability in performance.
The disclosed array substrate, fabrication method for the array substrate, and display panel are directed to solve one or more problems set forth above and other problems.